Hi! I bet you came here wondering about particle trails with commands. Well, I'm here to show you how!

Step One: Getting a Command Block

Simply type this command on your keyboard:

/give YOURUSERNAME minecraft:command_block

Replacing YOURUSERNAME with well, your name.

Step Two: Selecting the Particle

Right click the command block and paste this command into it:

/execute YOURUSERNAME ~ ~ ~ particle dripWater ~ ~0.1 ~ 0 0 0 100 1

Replace dripwater with what particle you want, and 1 with how many you want. Setting the 100 to 1 will slow it down. Also, set YOURUSERNAME to your name.

WARNING! Using higher numbers such as 100 for the amount of particles you want can lag your game! Also, using largeexplosion and hugeexplosion particles WILL CRASH YOUR GAME AND THE WORLD YOU USED WILL BE LOST!

If you want to see a list of particles, check the Minecraft Wiki page.

Step Three: A Few More Steps

Simply click Impulse until it changes to Repeat, and Needs Redstone to Always Active. Then press Done and enjoy your particle trail!

If you want to modify where the trail appears, change the ~ ~0.1 ~ to something of your choice. For example, setting it to ~3 ~0.9 ~5 will set it to 3 blocks away on the X axis, about the level of your player's torso, and 5 blocks away on the Z axis.

Have fun playing with your new particles!